A proper calibration of micromorph (a-Si/µc-Si) solar cells and modules, where current matching of bottom and top cell is a crucial factor, is complicated by the fact that the measured efficiency strongly depends on the spectral distribution of the incoming light. In the present work we compare the indoor and outdoor performance of a set of micromorph mini modules (10x10 cm2). In order to realize a proper calibration at standard test conditions (STC), the IV measurements require to be corrected to AM1.5 for the mismatch of the simulator¿s spectral distribution. This was done by realizing spectral response (SR) measurements of the multi-junction devices. We notice that the device under test changes its current-limiting behavior (from top to bottom limited), when measured under different spectral distributions of the light. Moreover, by comparing outdoor to indoor performance data we observe a very good agreement between the outdoor and the indoor measurement performed with one of our solar simulators. In addition, measurement related sweep-time effects were investigated. The results show that sweep times equal or higher than 1 ms show very good coincidence with the slow-speed measurements (1 s). This indicates that flashers or steady state solar simulators can be used with good accuracy to test these devices. These results will form the basis for the performance measurement of large-area multi-junction devices at ESTI.